linux-kernel - Re: [RFC PATCH 00/13][V3] kexec: A new system call to allow in kernel loading

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140612123658.GD9578@redhat.com>
Date:	Thu, 12 Jun 2014 08:36:58 -0400
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Dave Young <dyoung@...hat.com>
Cc:	linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
	ebiederm@...ssion.com, hpa@...or.com, mjg59@...f.ucam.org,
	greg@...ah.com, bp@...en8.de, jkosina@...e.cz, chaowang@...hat.com,
	bhe@...hat.com, akpm@...ux-foundation.org
Subject: Re: [RFC PATCH 00/13][V3] kexec: A new system call to allow in
 kernel loading

On Thu, Jun 12, 2014 at 01:42:03PM +0800, Dave Young wrote:
> On 06/03/14 at 09:06am, Vivek Goyal wrote:
> > Hi,
> > 
> > This is V3 of the patchset. Previous versions were posted here.
> > 
> > V1: https://lkml.org/lkml/2013/11/20/540
> > V2: https://lkml.org/lkml/2014/1/27/331
> > 
> > Changes since v2:
> > 
> > - Took care of most of the review comments from V2.
> > - Added support for kexec/kdump on EFI systems.
> > - Dropped support for loading ELF vmlinux.
> > 
> > This patch series is generated on top of 3.15.0-rc8. It also requires a
> > two patch cleanup series which is sitting in -tip tree here.
> > 
> > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/log/?h=x86/boot
> > 
> > This patch series does not do kernel signature verification yet. I plan
> > to post another patch series for that. Now bzImage is already signed
> > with PKCS7 signature I plan to parse and verify those signatures.
> > 
> > Primary goal of this patchset is to prepare groundwork so that kernel
> > image can be signed and signatures be verified during kexec load. This
> > should help with two things.
> > 
> > - It should allow kexec/kdump on secureboot enabled machines.
> > 
> > - In general it can help even without secureboot. By being able to verify
> >   kernel image signature in kexec, it should help with avoiding module
> >   signing restrictions. Matthew Garret showed how to boot into a custom
> >   kernel, modify first kernel's memory and then jump back to old kernel and
> >   bypass any policy one wants to.
> > 
> > Any feedback is welcome.
> 
> Hi, Vivek
> 
> For efi ioremapping case, in 3.15 kernel efi runtime maps will not be saved
> if efi=old_map is used. So you need detect this and fail the kexec file load.
> 
> Otherwise the patchset works for me.

Thanks Dave. I will make sure that in case of old mapping, kexec loading
fails. I don't want to be supporting that old "noefi" mode in this new
system call. Even SGI is planning to fix their firmware to support
1:1 mapping. 

Thanks
Vivek
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/